The first thing you want to be aware of is what a person means by the train station in Osaka. There are two that are easily confused. The first is the Japan Rail station called Shin-Osaka. This is where all the Shinkansen bullet trains arrive and depart. It connects to other JR lines that head into the city or go locally on to other places such as Kyoto. (The Midosuji Line (red) of the subway connects to Shin-Osaka as well, but if you are using the Japan Rail Pass, you can ride the JR line for free anyway.)
The other station is Osaka Station and it lies one stop from here on a JR train line — the JR Kyoto Line, be sure you take it the right direction — across the river deeper into the city. From there you can connect to subway lines, the JR Osaka Loop line, and other JR lines.
If you are with bags arriving by high-speed rail, it’s best to store bags at Shin-Osaka station.
Your first plan might be the coin-operated luggage lockers. Throw your bag in, drop the coin, take the key, and go. But as you can see in the photo, they aren’t terribly big.
No worries, there is a luggage storage room at Shin-Osaka station on the very first floor. It’s not far from the tourist information office. (Ignore the “information” booth at the bottom of the escalators coming off of the trains, unless you speak Japanese.)
Outside the Southern Shinkansen Gate at Shin-Osaka (which puts you on the 3rd floor of the station – see map but it won’t show the luggage room) you will go down two more floors to First Floor to get to the bus pickup. At the bottom of the steps to 1F turn left to see Central Gate and the bus and car area outside, as well as some bicycle parking just past a convenience store. Go left on the other side of that convenience store and you can see the luggage storage at the end of the walk up a short ramp for your suitcase’s rollers.
The man inside the check room will understand well why you are there so don’t worry too much if he speaks little or no English. He will take your bag and give you a token to retrieve it. (To be safe he even scrawled my name on the other half which he attached to my suitcase before filing it on a shelf behind the desk.)
It’s all very clear and easy and you must pay the attendant for the first day (500 yen) when you leave the bag. Remember that the luggage storage at Osaka is not 24 hours. The baggage storage opens at 9 a.m. and closes at 8 p.m.
The cost for each bag is 500 yen per day. After 5 days it goes up to 820 per day.